From houses and libraries to museums and hospitals, and everything in between, bricks are an integral part of today's built environment. Made from materials like mud, clay and concrete, we've used them for thousands of years.
But their production has a significant environmental impact which has led some to think creatively about how best to make these fundamental building blocks.
According to the Brick Development Association (BDA), the typical life cycle of a clay brick is 150 years. Once their primary-use ends, many bricks can be reused and repurposed in a range of ways.
There are challenges, however, especially when it comes to production. The BDA's Sustainability Report for 2019 describes brick manufacturing as an "energy intensive process" that "involves firing clay bricks to over 1000°C."
Another material that can be formed into bricks – or blocks – is concrete. It is made from combining water, a material like sand or crushed gravel – known as aggregate – and cement. According to a 2018 report from Chatham House, over 4 billion metric tons of cement are produced annually, which accounts for roughly 8% of worldwide carbon dioxide emissions.
While bricks are clearly crucial to the construction industry and the buildings we live and work in, there is now a move towards new manufacturing techniques that could reduce their impact on the environment.
The last few years have seen several companies develop interesting ways of producing bricks. U.S. based bioMASON, for instance, says it uses "microorganisms to grow cement," while in Scotland, one start-up wants to harness the power of recycling to produce bricks.
A spin-off from research carried out at Heriot-Watt University, Edinburgh, Kenoteq's K-Briq is an unfired brick produced from 90% construction and demolition waste. It is currently made at Hamilton Waste & Recycling, a waste management firm in Musselburgh, on the outskirts of Edinburgh.
According to the university, the K-Briq produces a tenth of the carbon dioxide emissions of a traditional-fired brick and also uses less than a tenth of the energy in its production.
"We use the inert waste – that means it's not going to change over time," Gabriela Medero, a professor at Heriot-Watt's School of Energy, Geoscience, Infrastructure and Society, told CNBC in a phone interview.
Medero, who is Kenoteq's technical director, went on to add that the material used in the K-briq could be a combination of things such as gravel, plaster board and bricks.
This summer, the K-Briq is set to be used at the Serpentine Pavilion installation in London – a prestigious architecture commission which showcases innovative design – while Medero said the company was looking to scale up production to 3 million bricks per year.
On the subject of finding more sustainable solutions and using different materials and processes in the years ahead, Medero explained that such a shift was "the only way forward. The way we are doing (things) as a construction sector … is not sustainable long term."
"It's the exploitation of natural resources, it's the… massive volumes of waste, together with the massive volumes of carbon emissions," she added. "We need to change."